CN104933219A - Method for acquiring full flow state simulation parameters of water lubricated thrust bearing - Google Patents

Abstract

The present invention discloses a method for acquiring simulation parameters of water lubricated thrust bearing. According to the characteristics of the low viscosity of water, the water lubricated thrust bearing may be turbulent, and the temperature field and elastic deformation may be affected. According to the present invention, a bearing bush is firstly divided into smallest calculation units, the flow state is determined according to a comparison between the Reynolds number of each calculation unit and the critical Reynolds number, wherein if the critical Reynolds number is exceeded, a turbulence is present, and otherwise a laminar flow is present. As such, corresponding Reynolds equation and energy equation are selected according to the flow state. Based on this, the impacts caused by the elastic deformation are further considered. According to the method, the pressure field, temperature field and elastic deformation of the thrust bearing are achieved through an iterative process. The torque balance and load balance are achieved by adjusting the parameters, thereby acquiring final simulation parameters. The entire numerical calculation model fully considers the impacts caused by different flow states, temperature field change and elastic deformation to the performance of the water lubricated thrust bearing. As compared against the prior model, the method according to the present invention is more comprehensive and accurate, and has a wider application scope.

Description

A kind of full fluidised form analog parameter acquisition methods of water lubricating thrust bearing

Technical field

The present invention relates to reaction core pump water lubricating thrust bearing field, specifically a kind of full fluidised form analog parameter acquisition methods of water lubricating thrust bearing.

Background technology

All-sealed pump, because of features such as its " zero leakages, volume is little, backup system is few ", more and more comes into one's own in reactor field and applies.Water lubricating thrust bearing is a critical component in glandless motor pump, and effect is the axial load of bearing the generations such as rotor deadweight and water flow pressure.Under the drive of thrust disc, in thrust bearing, continuous print moisture film can be produced, rely on hydrodynamic effect to provide axial bearing capacity, and the rotating part of thrust bearing friction pair and fixed part opposing spaced apart.Thus the load-carrying properties of water lubricating thrust bearing, life-span length, directly can affect reactor and primary Ioops reliability of operation and life-span.When conventional applicating fluid lubricating method project navigator analyzes water lubricating thrust bearing, have employed flowing moisture film is the supposition of laminar flow.Because heap is the cooling medium in primary Ioops with the lubricant of thrust bearing in all-sealed main pump, its viscosity is smaller, define (Re=ρ ω rh/ μ) according to the Reynolds number of thrust bearing, Reynolds number in water lubricating thrust bearing is larger, thus its flow state may become turbulent flow, can relate to the select permeability of determining flow regime and turbulence model.

By special topic and patent document retrieval, find that the document more close with the present invention is: the little tiger of the Qin of Dalian University of Technology " core pump water lubricating thrust bearing and mechanical sealing performance are studied " in 2013, " large-scale water lubricating thrust bearing load-carrying properties and the research of thrust bearing shoe valve Structure optimization " of Northcentral University Liu Qi in 2012, and " numerical analysis of ship water lubrication thrust bearing and the calculating " of Wu Zhuxin, Liu Zhenglin etc.Wherein front two sections of documents are not analyzed in conjunction with energy equation and elastic deformation equation, have ignored temperature field and thrust disc, bearing shell elastic deformation on the impact of the greasy property of water lubricating thrust bearing, the turbulent lubrication model simultaneously calculating employing has used for reference the derivation of the second inventor in " thrust bearing laminar flow is to the theoretical analysis of turbulent transition region " (see " lubrication and sealing ", 1997,4:5 ~ 6).In addition, these three sections of documents all can only calculate for the lubricating status of complete laminar flow or complete turbulent flow, can not process in water lubricating thrust bearing the full flow simulation problem that simultaneously there is laminar flow and turbulent lubrication.

Through new patent searching, do not retrieve the literature record of any lubricating status when coexisting about laminar flow in water lubricating thrust bearing and turbulent flow.

Summary of the invention

The object of the present invention is to provide a kind of full fluidised form analog parameter acquisition methods of water lubricating thrust bearing, solve the problem that current water lubricating thrust bearing analog parameter acquisition methods can not be used for laminar flow, turbulent flow coexisting state.

Object of the present invention is achieved through the following technical solutions.

A kind of full fluidised form analog parameter acquisition methods of water lubricating thrust bearing: bearing shell is divided into some computing units, judge that the fluidised form of each computing unit is laminar flow or turbulent flow, and select the Reynolds equation of corresponding description fluid film pressure distribution and describe the energy equation of its Temperature Distribution, each unit combination is got up and is realized the balance between the pressure field of thrust bearing entirety, temperature field and elastic deformation by iteration, realized equalising torque and the counterweight balance of thrust bearing again by adjustment parameter, thus obtain final analog parameter.

The present inventor finds in the practical application for many years of water lubricating thrust bearing, existing analog parameter obtain be all for complete laminar flow or completely the lubricating status of turbulent flow carry out calculating and obtain, and such understanding is actually the unilateral in other words conj.or perhaps of existing defects, the result that such analogy method obtains is not accurate enough.In addition, in years of researches, applicant finds: bearing shell and thrust disc bear pressure can produce certain elastic deformation, thus changes the water film thickness distribution in thrust bearing.Water film thickness changes in distribution can change the pressure field distribution between thrust disc and thrust bearing shoe valve then, and pressure distribution is directly influence elastane distortion conversely again, and thus this is a typical fluid structurecoupling problem.According to such discovery, applicant has made improvement to existing analogy method, has counted the elastic deformation of temperature variation on the viscosity influence of water and thrust disc and bearing shell to the impact of water film thickness.In calculating, bearing surface is divided into enough tiny computing unit, then judge that the fluidised form of fluid is laminar flow or turbulent flow according to the Reynolds number size of each computing unit, thus the analog parameter of all running statuses that may be able to occur in self-adaptation water lubricating thrust bearing obtains.Relative to the method in document before, more comprehensively, accurately, the scope of application is also wider for method model provided by the invention: add energy equation and elastic deformation equation, considers the impact of temperature field and elastic deformation, makes model more comprehensive and accurate; Automatically choose corresponding equation after judging fluidised form to calculate, be not only applicable to the Lubrication Analysis of complete laminar flow and complete turbulent flow, and be applicable to Lubrication Analysis when laminar-turbulent flow coexists, extend the scope of application of original computing method.

Further, the condition that fluidised form judges is: the Reynolds number of each computing unit and critical Reynolds number are compared, if exceed critical Reynolds number, then this unit fluidised form is turbulent flow, otherwise is laminar flow.The phenomenon across fluidised form that can correctly may exist in Simulated Water lubricating thrust bearing like this, fluidised form directly becomes turbulent flow from laminar flow simultaneously and in thrust bearing, and the theory that there is not vortex cavity conforms to.Judge fluidised form and select corresponding equation all can automatically complete, thus can obtain water lubricating thrust bearing the analog parameter of likely operating condition.

Further, suitable turbulence model can be selected by carrying out contrasting with trial value, and adjustment critical Reynolds number strengthens the accuracy of model; Or directly adopt engineering to commonly use turbulence model and critical Reynolds number value to obtain analog parameter.The scope of application of different turbulent models is different with accuracy, adds the critical Reynolds number that can adjust flexibly, and whole model elasticity is stronger, more accurately, simultaneously more targeted.If do not have trial value, engineering is directly selected to commonly use turbulence model and critical Reynolds number also can ensure certain accuracy in computation.

The present invention compared with prior art, there is following advantage and beneficial effect: the full fluidised form analog parameter acquisition methods that the invention provides a kind of water lubricating thrust bearing, automatically laminar flow or turbulent flow computing unit is divided into according to the Reynolds number size of each computing unit of bearing surface, relative to traditional complete laminar flow or complete turbulence meter calculation and Analysis, this method is more comprehensively, accurately, and applied widely.

Accompanying drawing explanation

Fig. 1 is the structure principle chart of thrust bearing in the embodiment of the present invention;

Determining flow regime figure when laminar flow and turbulent flow coexist in Fig. 2 embodiment of the present invention.

Mark and corresponding parts title in accompanying drawing:

1-thrust disc, 2-fan-shaped bearing shell, 3-rotor.

Embodiment

Below in conjunction with embodiment, the present invention is described in further detail, but embodiments of the present invention are not limited thereto.

Embodiment:

Schematic diagram as shown in Figure 1, glandless motor pump water lubricating thrust bearing friction pair is composed of with the fan-shaped bearing shell 2 be circular layout by discoid thrust disc 1, when glandless motor pump runs, thrust disc 1 is fixedly connected with rotor 3 and rotates around axle center, and bearing shell 2 is the stationary parts that surface tilts.To be acted on bearing shell 2 by thrust disc 1 due to the axial load F of thrust bearing and keep down, when thrust disc 1 rotates, between thrust disc 1 and fan-shaped bearing shell 2, can certain thickness be formed, the flowing moisture film that can carry.

The analog parameter of this water lubricating thrust bearing is obtained and carries out by the following method.

(1) bearing shell is divided into some computing units, judges that the fluidised form of each computing unit is laminar flow or turbulent flow.Wherein, the Reynolds equation of the moisture film pressure distribution of description unit under laminar condition:

$\frac{\∂}{\∂r}\left(\frac{{\mathrm{rh}}^3}{12\mathrm{\μ}}\frac{\∂p}{\∂r}\right)+\frac{\∂}{\∂\mathrm{\θ}}\left(\frac{h^3}{12\mathrm{\μ}}\frac{\∂p}{r\∂\mathrm{\θ}}\right)=\frac{\mathrm{\ωr}}{2}\frac{\∂h}{\∂\mathrm{\θ}}+\frac{{\mathrm{\ω}}^2}{40}\frac{\∂}{\∂r}\left(\frac{{\mathrm{\ρh}}^3{r}^2}{\mathrm{\μ}}\right)---\left(1\right)$

In formula, h is water film thickness, and μ is the viscosity of water, and p is moisture film pressure, and ω is thrust bearing rotating speed, and ρ is the density of water.The energy equation of water film temperature distribution is described:

$\left\{\begin{array}{c}-\mathrm{\ρ}{C}_p(q_r\frac{\∂T}{\∂r}+q_{\mathrm{\θ}}\frac{1}{r}\frac{\∂T}{\∂\mathrm{\θ}})=q_r\frac{\∂p}{\∂r}+q_{\mathrm{\θ}}\frac{1}{r}\frac{\∂p}{\∂\mathrm{\θ}}-(\frac{h}{2r}\frac{\∂p}{\∂\mathrm{\θ}}+\frac{\mathrm{\μ\ωr}}{h})\mathrm{\ωr}\\ q_r=-\frac{h^3}{12\mathrm{\μ}}\frac{\∂p}{\∂r}+\frac{{\mathrm{\ρh}}^{3}r{\mathrm{\ω}}^2}{40\mathrm{\μ}},q_{\mathrm{\θ}}=-\frac{h^3}{12\mathrm{\μ}}\frac{\∂p}{r\∂\mathrm{\θ}}+\frac{\mathrm{r\ωh}}{2}\end{array}\right.---\left(2\right)$

C in formula _pfor the specific heat at constant pressure of water, T is water film temperature.

Under turbulence state, the Reynolds equation of moisture film pressure distribution is described:

$\left\{\begin{array}{c}\frac{\∂}{\∂r}\left(G_r\frac{{\mathrm{rh}}^3}{\mathrm{\μ}}\frac{\∂p}{\∂r}\right)+\frac{\∂}{\∂\mathrm{\θ}}\left(G_{\mathrm{\θ}}\frac{h^3}{\mathrm{\μ}}\frac{\∂p}{r\∂\mathrm{\θ}}\right)=\frac{\mathrm{\ωr}}{2}\frac{\∂h}{\∂\mathrm{\θ}}+\\ \frac{\∂}{\∂r}\left(\frac{\mathrm{\ρ}}{\mathrm{\μ}}\right[M_1\frac{h^7}{{\mathrm{\μ}}^2{r}^2}{\left(\frac{\∂p}{\∂\mathrm{\θ}}\right)}^2-M_2\frac{{\mathrm{\ωh}}^5}{\mathrm{\μ}}\frac{\∂p}{\∂\mathrm{\θ}}+M_3{r}^2{\mathrm{\ω}}^2{h}^3\left]\right)\\ M_1=\frac{1}{144}{G}_r{G_{\mathrm{\θ}}}^2,M_2=\frac{1}{12}{G}_r{G}_{\mathrm{\θ}}\\ M_3=(k+\frac{1}{4})G_r,k=0.885{\mathrm{Re}}^{-0.367}\end{array}\right.---\left(3\right)$

Energy equation:

$\left\{\begin{array}{c}-\mathrm{\ρ}{C}_p(q_r\frac{\∂T}{\∂r}+q_{\mathrm{\θ}}\frac{1}{r}\frac{\∂T}{\∂\mathrm{\θ}})=q_r\frac{\∂p}{\∂\mathrm{\θ}}+q_{\mathrm{\θ}}\frac{1}{r}\frac{\∂p}{\∂\mathrm{\θ}}-(\frac{h}{2r}\frac{\∂p}{\∂\mathrm{\θ}}+\frac{1}{12G_{\mathrm{\θ}}}\frac{\mathrm{\μ\ωr}}{h})\mathrm{\ωr}\\ q_r=-G_r\frac{h^3}{\mathrm{\μ}}\frac{\∂p}{\∂r}+\frac{\mathrm{\ρ}}{\mathrm{\μr}}[M_1\frac{h^7}{{\mathrm{\μ}}^2{r}^2}{\left(\frac{\∂p}{\∂\mathrm{\θ}}\right)}^2-M_2\frac{{\mathrm{\ωh}}^5}{\mathrm{\μ}}\frac{\∂p}{\∂\mathrm{\θ}}+M_3{r}^2{\mathrm{\ω}}^2{h}^3]\\ q_{\mathrm{\θ}}=-G_{\mathrm{\θ}}\frac{h^3}{\mathrm{\μ}}\frac{\∂p}{r\∂\mathrm{\θ}}+\frac{\mathrm{\ωrh}}{2}\end{array}\right.---\left(4\right)$

In formula, the physical significance of each parameter is with the equation under above-mentioned laminar condition, wherein G _r, G _θbe respectively footpath, circumferential turbulivity, in different turbulence models, the expression-form of turbulivity is different, as follows:

$\left\{\begin{array}{c}{G}_r={(12+A\·{\mathrm{Re}}^{\mathrm{\α}})}^{-1}\\ G_{\mathrm{\θ}}={(12+B\·{\mathrm{Re}}^{\mathrm{\β}})}^{-1}\end{array}\right.---\left(5\right)$

The coefficient of different turbulent models is as shown in the table:

The condition that fluidised form judges is: the Reynolds number of each computing unit and critical Reynolds number are compared, if exceed critical Reynolds number, then this unit fluidised form is turbulent flow, otherwise is laminar flow.

Select suitable turbulence model by carrying out contrasting with trial value, and adjustment critical Reynolds number strengthens the accuracy of model; Or directly adopt engineering to commonly use turbulence model (Constantinescu or Ng-Pan model) and critical Reynolds number value (Re _c=1500) analog parameter is obtained.

(2) select the Reynolds equation of corresponding description fluid film pressure distribution and describe the energy equation of its Temperature Distribution, each unit combination got up and realized the balance between the pressure field of thrust bearing entirety, temperature field and elastic deformation by iteration, elastic deformation equation describes the impact of moisture film pressure on the elastic deformation of thrust bearing shoe and thrust disc:

$\mathrm{\δ}(r,\mathrm{\θ})=\frac{1}{{\mathrm{\πE}}_0}{\∫}_0^{\mathrm{\β}}{\∫}_{r_1}^{r_2}\frac{p(\mathrm{\ζ},\mathrm{\χ})\mathrm{\ζd\ζd\χ}}{\sqrt{r^2+{\mathrm{\ζ}}^2-2\mathrm{r\ζ}\·\cos (\mathrm{\θ}-\mathrm{\χ})}}---\left(6\right)$

For δ is proof resilience deflection in formula, E ₀for complex elastic-modulus, its expression formula is:

$\frac{1}{E_0}=\frac{1-{{\mathrm{\υ}}_1}^2}{E_1}+\frac{1-{\mathrm{\υ}}_2^2}{E_2}---\left(7\right)$

Wherein E ₁, ν ₁, E ₂, ν ₂be respectively Young modulus and the Poisson ratio of bearing shell and thrust disc;

(3) realized equalising torque and the counterweight balance of thrust bearing again by adjustment parameter, thus obtain final analog parameter.

According to above implementation step, the analog parameter of the water lubricating thrust bearing of steady-state operation can be obtained.The above is only preferred embodiment of the present invention, not does any pro forma restriction to the present invention, every according in technical spirit of the present invention to any simple modification, equivalent variations that above embodiment is done, all fall within protection scope of the present invention.

Claims (3)

1. the full fluidised form analog parameter acquisition methods of a water lubricating thrust bearing: bearing shell is divided into some computing units, judge that the fluidised form of each computing unit is laminar flow or turbulent flow, and select the Reynolds equation of corresponding description fluid film pressure distribution and describe the energy equation of its Temperature Distribution, each unit combination is got up and is realized the balance between the pressure field of thrust bearing entirety, temperature field and elastic deformation by iteration, realized equalising torque and the counterweight balance of thrust bearing again by adjustment parameter, thus obtain final analog parameter.

2. method according to claim 1, is characterized in that, the condition that fluidised form judges is: the Reynolds number of each computing unit and critical Reynolds number are compared, if exceed critical Reynolds number, then this unit fluidised form is turbulent flow, otherwise is laminar flow.

3. method according to claim 1 and 2, is characterized in that, select suitable turbulence model, and adjustment critical Reynolds number strengthens the accuracy of model by carrying out contrasting with trial value; Or directly adopt engineering to commonly use turbulence model and critical Reynolds number value to obtain analog parameter.